X-ray radiography of soil cores was used as the primary test method to determine the reasons for the permeation of perchloroethylene into apparently impermeable clay layers at a hazardous chemical spill site. X-ray powder diffractometry, scanning electron microscopy, and chemical analysis were also performed to characterize the materials and structures observed in the soil cores through X radiography and to verify the presence or absence of perchloroethylene.

X-ray radiography proved to be an invaluable tool in the examination of the soil structure and in the solution of the problem. Results showed the presence of a three-dimensional network of iron-lined fissures, concretions, and roots in otherwise low permeability clay. These conduits were responsible for the rapid permeation of the perchloroethylene.